Effects of turbulence, resistivity and boundary conditions on helicoidal flow collimation: consequences for the Von-Kármán-Sodium dynamo experiment

@article{Varela2017EffectsOT,
  title={Effects of turbulence, resistivity and boundary conditions on helicoidal flow collimation: consequences for the Von-K{\'a}rm{\'a}n-Sodium dynamo experiment},
  author={Jacobo Varela and S. Brun and B{\'e}reng{\`e}re Dubrulle and Caroline Nore},
  journal={Physics of Plasmas},
  year={2017},
  volume={24},
  pages={053518}
}
We present hydrodynamic and magneto-hydrodynamic simulations of a liquid sodium flow using the compressible MHD code PLUTO to investigate the magnetic field regeneration in the Von-Karman-Sodium dynamo experiment. The aim of the study is to analyze the influence of the fluid resistivity and turbulence level on the collimation by helicoidal motions of a remnant magnetic field. We use a simplified Cartesian geometry to represent the flow dynamics in the vicinity of one cavity of a multi-blades… 
View PDF on arXiv
4 Citations
Background Citations
1
Results Citations
1

4 Citations

Parametric study and optimization trends for the Von-Kármán-sodium dynamo experiment

We present magneto-hydrodynamic simulations of liquid sodium flow performed with the PLUTO compressible MHD code. We investigated the influence of the remanent magnetic field orientation and…

Effect of electromagnetic boundary conditions on convective dynamo onset

We present a high-order numerical study of the dependence of the dynamo onset on different electromagnetic boundary conditions, in convecting Boussinesq flows forced by a temperature gradient.…

Rossby and Magnetic Prandtl Number Scaling of Stellar Dynamos

Rotational scaling relationships are examined for the degree of equipartition between magnetic and kinetic energies in stellar convection zones. These scaling relationships are approached from two…

Multi-Vortex Regulation for Efficient Fluid and Particle Manipulation in Ultra-Low Aspect Ratio Curved Microchannels

A simple semicircular microchannel with an ultra-low aspect ratio is developed to interrogate the unique formations of the helical vortex and Dean vortex by introducing order micro-obstacles and offers insights into the geometry-induced multi-vortex mechanism.

References

SHOWING 1-10 OF 34 REFERENCES

Role of boundary conditions in helicoidal flow collimation: Consequences for the von Kármán sodium dynamo experiment.

It is shown that the impinging of the large-scale flow upon the impeller generates a coherent helicoidal vortex inside the blades, located at a distance from the upstream blade piloted by the incident angle of the flow.

Direct numerical simulation of the axial dipolar dynamo in the Von Kármán Sodium experiment

For the first time, a direct numerical simulation of the incompressible, fully nonlinear, magnetohydrodynamic (MHD) equations for the Von Kármán Sodium (VKS) experiment is presented with the two…

Global-Scale Turbulent Convection and Magnetic Dynamo Action in the Solar Envelope

The operation of the solar global dynamo appears to involve many dynamical elements, including the generation of fields by the intense turbulence of the deep convection zone, the transport of these…

Numerical study of impeller-driven von Kármán flows via a volume penalization method

Studying strongly turbulent flows is still a major challenge in fluid dynamics. It is highly desirable to have comparable experiments to obtain a better understanding of the mechanisms generating…

The von Kármán Sodium experiment: Turbulent dynamical dynamos

The von Karman Sodium (VKS) experiment studies dynamo action in the flow generated inside a cylinder filled with liquid sodium by the rotation of coaxial impellers (the von Karman geometry). We first…

Toward an experimental von Kármán dynamo: Numerical studies for an optimized design

Numerical studies of a kinematic dynamo based on von Karman type flows between two counterrotating disks in a finite cylinder are reported. The flow has been optimized using a water model experiment,…

Impact of impellers on the axisymmetric magnetic mode in the VKS2 dynamo experiment.

It is conjecture that the dynamo action achieved in this experiment may not be related to the turbulence in the bulk of the flow, but rather to the alpha effect induced by the impellers.

A numerical model of the VKS experiment

We present numerical simulations of the magnetic field generated by the flow of liquid sodium driven by two counter-rotating impellers (VKS experiment). Using a kinematic code in cylindrical…

Simulations of the anisotropic kinetic and magnetic alpha effects

The validity of a closure called the minimal tau approximation (MTA), is tested in the context of dynamo theory, wherein triple correlations are assumed to provide relaxation of the turbulent…

Generation of a magnetic field by dynamo action in a turbulent flow of liquid sodium.

We report the observation of dynamo action in the von Kármán sodium experiment, i.e., the generation of a magnetic field by a strongly turbulent swirling flow of liquid sodium. Both mean and…